Reverse Osmosis Filter Stops Making Water

I have a RO system that stops producing water periodically. If I turn off the supply water for 20 minutes or so and then switch back on it clears itself and starts producing again.

I changed all the filters, including the membrane, same problem. It gets worse in the cold winter weather, so I have routed the incoming supply water through copper tubing in a warm part of the basement to increase water temperature, but it still stops. I have an Aquatec permeate pump installed for added efficiency. I monitored incoming water pressure which fluctuates from 40-80 PSI (city water pressure). I also have a TDS monitor installed. I do have a water softener and the water supply had been sourced from the line after the softener.

Installation issues that may affect this RO unit are:

- Installed in basement with a run of about 30-40 feet to faucet.
- Used 1/2" PEX line from basement RO tank to faucet.
- Drain line goes up from filter about 4 feet and then over and down to a drain.
- Water pressure fluctuating.

If I am not mistaking, you must remove the auto shut off in order for the permeate pump to function. If this has already been done, I think the pump is causing the problem. It's sticking not allowing the unit to turn back on after the tank is full and drained again. If you still have the auto shut off attached, then that is the problem.

It has been about 11 years since I have installed a permeate pump on a RO. I was instructed to remove the auto shut off. The pump acts the same as the shut off in that it uses hydraulics to function. Once the pressure on the permeate side is greater than the drain, the piston stops the drain water. Once water is used, the pumps turns on and allows water to flow to the drain again.
Just found this. It clearly states to remove the auto shut off.http://www.pwgazette.com/installpermeate.htm

I will remove the auto shutoff valve and see if it makes a difference. I did have this problem prior to installing the Permeate pump, but I am willing to try anything because I have tried everything else I can possibly think of short of replacing the whole RO system with a new one.

Any chance the fact that I took the output from the RO and plumbed it upstairs using 1/2" pex line is a problem? I was trying to determine if with the increase in water capacity it would create more hydraulic head pressure which could cause this to problem.

Any chance the fact that I took the output from the RO and plumbed it upstairs using 1/2" pex line is a problem? I was trying to determine if with the increase in water capacity it would create more hydraulic head pressure which could cause this to problem.

Click to expand...

That shouldn't cause the problem. It could be that the auto shout off was bad to begin with. Let me know how it goes.

Yes, I will get back as to whether removing the auto shutoff valve completely cures the problem. It may be a while though, as it can work for weeks just fine and then act up.

For the record, the auto shutoff valve was the first thing I replaced when this problem started. It happened the first winter after I installed the unit and seems to happen much more often in cold weather.